The Full Wiki

Kingdom (biology): Wikis

  
  

Did you know ...


More interesting facts on Kingdom (biology)

Include this on your site/blog:

Encyclopedia

From Wikipedia, the free encyclopedia

Life Domain Kingdom Phylum Class Order Family Genus Species

The hierarchy of biological classification's eight major taxonomic ranks. A domain contains one or more kingdoms. Intermediate minor rankings are not shown.

In biological taxonomy, kingdom or regnum is a taxonomic rank in either (historically) the highest rank, or (in the new three-domain system) the rank below domain. Each kingdom is divided into smaller groups called phyla (or in some contexts these are called "divisions"). Currently, many textbooks from the United States use a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea, Bacteria) while British and Australian textbooks may describe five kingdoms (Animalia, Plantae, Fungi, Protista, and Prokaryota or Monera). The classifications of taxonomy are life, domain, kingdom, phylum, class, order, family, genus, and species.

Contents

Early concepts

Carolus Linnaeus distinguished two kingdoms of living things: Animalia for animals and plantae for plants (Linnaeus also included minerals, placing them in a third kingdom, Mineralia). Linnaeus divided each kingdom into classes, later grouped into phyla for animals and divisions for plants. It gradually became apparent how important the prokaryote/eukaryote distinction is, and Stanier and van Niel popularized Édouard Chatton's proposal in the 1960s to divide them.[1]

Cladistics does not use this term, because one of the fundamental premises of cladistics is that the evolutionary tree is so deep and so complex that it is inadvisable to set a fixed number of levels.

Five kingdoms

Robert Whittaker recognized an additional kingdom for the Fungi. The resulting five-kingdom system, proposed in 1969, has become a popular standard and with some refinement is still used in many works and forms the basis for newer multi-kingdom systems. It is based mainly on differences in nutrition; his Plantae were mostly multicellular autotrophs, his Animalia multicellular heterotrophs, and his Fungi - multicellular saprotrophs. The remaining two kingdoms, Protista and Monera, included unicellular and simple cellular colonies.[2]

Six kingdoms

In the years around 1980, there was an emphasis on phylogeny and redefining the kingdoms to be monophyletic groups, groups made up of relatively closely related organisms. The Animalia, Plantae, and Fungi were generally reduced to core groups of closely related forms, and the others placed into the Protista. Based on RNA studies, Carl Woese divided the prokaryotes (Kingdom Monera) into two kingdoms, called Eubacteria and Archaebacteria. Carl Woese attempted to establish a Three Primary Kingdom (or Urkingdom) system in which Plants, Animals, Protista, and Fungi were lumped into one primary kingdom of all eukaryotes. The Eubacteria and Archaebacteria made up the other two urkingdoms. The initial use of "six Kingdom systems" represents a blending of the classic Five Kingdom system and Woese's Three Domain system. Such six Kingdom systems have become standard in many works.[3]

A variety of new eukaryotic kingdoms were also proposed, but most were quickly invalidated, ranked down to phyla or classes, or abandoned. The only one which is still in common use is the kingdom Chromista proposed by Cavalier-Smith, including organisms such as kelp, diatoms, and water moulds. Thus the eukaryotes are divided into three primarily heterotrophic groups, the Animalia, Fungi, and Protozoa, and two primarily photosynthetic groups, the Plantae (including red and green algae) and Chromista. However, it has not become widely used because of uncertainty over the monophyly of the latter two kingdoms.

Woese stresses genetic similarity over outward appearances and behavior, relying on comparisons of ribosomal RNA genes at the molecular level to sort out classification categories. A plant does not look like an animal, but at the cellular level, both groups are eukaryotes, having similar subcellular organization, including cell nuclei, which the Eubacteria and Archaebacteria do not have. More importantly, plants, animals, fungi, and protists are more similar to each other in their genetic makeup at the molecular level, based on RNA studies, than they are to either the Eubacteria or Archaebacteria. Woese also found that all of the eukaryotes, lumped together as one group, are more closely related, genetically, to the Archaebacteria than they are to the Eubacteria. This means that the Eubacteria and Archaebacteria are separate groups even when compared to the eukaryotes. So, Woese established the three-domain system, clarifying that all the eukaryotes are more closely genetically related compared to their genetic relationship to either the bacteria or the archaebacteria, without having to replace the "six kingdom systems" with a three kingdom system. The Three Domain system is a "six kingdom system" that unites the eukaryotic kingdoms into the Eukarya Domain based on their relative genetic similarity when compared to the Bacteria domain and the Archaea domain. Woese also recognized that the Protista kingdom is not a monophyletic group and might be further divided at the level of kingdom. Others have divided the Protista kingdom into the Protozoa and the Chromista, for instance.

Recent proposals

Kingdom classification is in flux due to ongoing research and discussion. As new findings and technologies become available they allow the refinement of the model. For example, gene sequencing techniques allow the comparison of the genome of different groups (Phylogenomics).

Summary

Linnaeus
1735[4]
2 kingdoms
Haeckel
1866[5]
3 kingdoms
Chatton
1925[6][7]
2 empires
Copeland
1938[8][9]
4 kingdoms
Whittaker
1969[2]
5 kingdoms
Woese et al.
1977[3][10]
6 kingdoms
Woese et al.
1990[11]
3 domains
(not treated) Protista Prokaryota Monera Monera Eubacteria Bacteria
Archaebacteria Archaea
Eukaryota Protista Protista Protista Eukarya
Vegetabilia Plantae Fungi Fungi
Plantae Plantae Plantae
Animalia Animalia Animalia Animalia Animalia


Note that the equivalences in this table are not perfect. e.g. Haeckel placed the red algae (Haeckel's Florideae; modern Florideophyceae) and blue-green algae (Haeckel's Archephyta; modern Cyanobacteria) in his Plantae.

In 1998, Cavalier-Smith[12] proposed that Protista should be divided into 2 new kingdoms: Chromista the phylogenetic group of golden-brown algae that includes those algae whose chloroplasts contain chlorophylls a and c, as well as various colorless forms that are closely related to them, and Protozoa, the kingdom of protozoans[13]. This proposal has not been widely adopted, although the question of the relationships between different domains of life remains controversial.[14]

Empires Kingdoms
Prokaryota Bacteria
Eukaryota Animalia Plantae Fungi Chromista Protozoa

See also

References

  1. ^ Stanier RY, Van Niel CB (1962). "The concept of a bacterium". Archiv Für Mikrobiologie 42: 17–35. PMID 13916221. 
  2. ^ a b Whittaker RH (January 1969). "New concepts of kingdoms or organisms. Evolutionary relations are better represented by new classifications than by the traditional two kingdoms". Science 163 (863): 150–60. PMID 5762760. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=5762760. 
  3. ^ a b Balch WE, Magrum LJ, Fox GE, Wolfe RS, Woese CR (August 1977). "An ancient divergence among the bacteria". J. Mol. Evol. 9 (4): 305–11. doi:10.1007/BF01796092. PMID 408502. 
  4. ^ C. Linnaeus (1735). Systemae Naturae, sive regna tria naturae, systematics proposita per classes, ordines, genera & species. 
  5. ^ E. Haeckel (1866). Generelle Morphologie der Organismen. Reimer, Berlin. 
  6. ^ É. Chatton (1925). "Pansporella perplexa. Réflexions sur la biologie et la phylogénie des protozoaires". Ann. Sci. Nat. Zool 10-VII: 1–84. 
  7. ^ É. Chatton (1937). Titres et Travaux Scientifiques (1906–1937). Sette, Sottano, Italy. 
  8. ^ H. Copeland (1938). "The kingdoms of organisms". Quarterly review of biology 13: 383–420. doi:10.1086/394568. 
  9. ^ H. F. Copeland (1956). The Classification of Lower Organisms. Palo Alto: Pacific Books. 
  10. ^ Woese CR, Fox GE (November 1977). "Phylogenetic structure of the prokaryotic domain: the primary kingdoms". Proc. Natl. Acad. Sci. U.S.A. 74 (11): 5088–90. PMID 270744. 
  11. ^ Woese C, Kandler O, Wheelis M (1990). "Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya.". Proc Natl Acad Sci U S A 87 (12): 4576–9. doi:10.1073/pnas.87.12.4576. PMID 2112744. PMC 54159. http://www.pnas.org/cgi/reprint/87/12/4576. 
  12. ^ Cavalier-Smith T (August 1998). "A revised six-kingdom system of life". Biological Reviews of the Cambridge Philosophical Society 73 (3): 203–66. doi:10.1111/j.1469-185X.1998.tb00030.x. PMID 9809012. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1464-7931&date=1998&volume=73&issue=3&spage=203. 
  13. ^ Cavalier-Smith T (2006). "Protozoa: the most abundant predators on earth" (pdf). Microbiology Today: 166–7. http://www.sgm.ac.uk/pubs/micro_today/pdf/110605.pdf. 
  14. ^ Walsh DA, Doolittle WF (April 2005). "The real 'domains' of life". Current Biology 15 (7): R237–40. doi:10.1016/j.cub.2005.03.034. PMID 15823519. http://linkinghub.elsevier.com/retrieve/pii/S0960-9822(05)00300-3. 

External links


Simple English

Kingdom is the highest rank used in the biological taxonomy of all organisms. Each kingdom is split into phyla.

There are 5 kingdoms in taxonomy. Every living thing comes under one of these 5 kingdoms. They are:

Monera - the most simple living things.
Protista - eukaryotes with only one cell.
Fungi - mushrooms, mold and other fungi.
Plantae - all plants, such as trees and grass.
Animalia - all animals, including people.

Kingdom is the king in the mneomic, or a saying to help a person remember something, King Phillip Came Over For Great Spaghetti.

Summary

Linnaeus
1735
2 kingdoms
Haeckel
1866
3 kingdoms
Chatton
1937
2 empires
Copeland
1956
4 kingdoms
Whittaker
1969
5 kingdoms
Woese et al.
1977
6 kingdoms
Woese et al.
1990[1]
3 domains
(not treated) Protista Prokaryota Monera Monera Eubacteria Bacteria
Archaebacteria Archaea
Eukaryota Protoctista Protista Protista Eukarya
Vegetabilia Plantae Fungi Fungi
Plantae Plantae Plantae
Animalia Animalia Animalia Animalia Animalia

Sometimes entries in the table, which are next to each other, do not match perfectly. For example, Haeckel placed the red algae (Haeckel's Florideae; modern Florideophyceae) and blue-green algae (Haeckel's Archephyta; modern Cyanobacteria) in his Plantae, but in modern classifications they are considered protists and bacteria respectively. However, despite this and other failures of equivalence, the table gives a useful simplification.

References

  1. Carl R. Woese, Otto Kandler, Mark L. Wheelis: "Towards a Natural System of Organisms: Proposal for the domains Archaea, Bacteria, and Eucarya", doi:10.1073/pnas.87.12.4576


Citable sentences

Up to date as of December 13, 2010

Unfortunately, we could not find any sentences from other sites similar to those above.








Got something to say? Make a comment.
Your name
Your email address
Message